The use of bleaching agents in washing procedures and as constituents of detergent compositions is well known in the art. Thus, bleaching agents are incorporated in or sold as constituents of a major part of the commercially available detergent compositions. Important conventional bleaching agents incorporated in detergent compositions are compounds which act as precursors of hydrogen peroxide formed in the course of the washing procedure. Perborates and percarbonates are the most important examples of compounds which are employed as bleaching agents and which exert a bleaching effect in this fashion.
It has been found that peroxidases, utilizing hydrogen peroxide as substrate, are able to enhance the bleaching effect of hydrogen peroxide during washing. The use of peroxidases for bleaching stains on fabrics is described in WO 89/09813. It has also been found that coloured substances leached from dyed fabrics can be bleached by means of peroxidases together with hydrogen peroxide. The use of peroxidases for inhibiting dye transfer in this way is described in WO 91/05839.
Variants of peroxidases which have a higher stability towards hydrogen peroxide than the wild type have also been described, see WO 93/24618 and WO 95/10602.
In WO 95/10602 it is shown that the Coprinus cinereus peroxidase variant (M242I+Y272F+E239K) has a good hydrogen peroxide stability at alkaline pH.
It is the purpose of this invention to create new Coprinus cinereus peroxidase variants which perform better than the ones previously disclosed at pH 7-10 and 30-50.degree. C. (typical washing conditions).